Methane concentrations were determined for air samples collected over the western Pacific and the Antarctic Ocean in the years from 1978 to 1986. The latitudinal distribution from 35°N to 65°S revealed a decrease in methane concentration towards south, with two sharp gradients around 20°N and the intertropical convergence zone (ITCZ). The methane concentrations south of ITCZ were much lower than those in the Northern Hemisphere. The average concentrations of methane in samples collected over the western North Pacific (9°N–24°N) indicate an almost linear increase from 1978 to 1986 with no significant fluctuation of the annual rate of methane increase. The average rate of the increase from 1978 to 1986 was calculated to be 17 ± 2 ppb/yr over the western North Pacific, and that over the Antarctic Ocean was estimated to be 16–17 ppb/yr from 1978 to 1984.

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The isotopic compositions of Mg in 5 individual stony spherules from deep-sea sediments have been measured. The spherules are composed of olivine, glass, and magnetite, and considered to be of extraterrestrial origin. No significant mass fractionation of up to 2 per mil per amu was recognized. One sample showed a small but significant non-linear ²⁶Mg isotopic effect (δ²⁶Mg = +1.2 per mil) similar to that reported in interplanetary dust particles (IDPs). Based on Mg isotopic compositions of the spherules, we suggest that either vaporization mass loss of parent meteoroids of stony spherules was not so large, usually less than ∼20%, or ablative mass loss occurred effectively during entry into the Earth's atmosphere, and that physicochemical fractionations took place in parent meteoroids could be related to those of primitive IDPs. The processes responsible for the non-linear effect of ²⁶Mg, however, remain undefined.

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To understand the effect of rock types on the fractionation of light hydrocarbons in natural gases during migration in sedimentary rocks, the retention time of each hydrocarbon (C₁, C₂, C₃, i-C₄, i-C₅ and n-C₅) was measured using gaschromatografic columns packed with various rock and mineral samples. The fractionation occurred when the samples contained expandable clay minerals or zeolites. The order of retention times depended on the kind of clay minerals or zeolites present in the column. When montmorillonite, halloysite, vermiculite and mordenite were used, the order was C₁ < C₂ < C₃ < i-C₄ < n-C₄ < i-C₅ < n-C₅. When clinoptilolite was used, the order was C₁ < i-C₄ < C₂ < i-C₅ < C₃ < n-C₄, probably because the pore size of clinoptilolite is somewhere between the cross-sectional diameters of n-alkanes and i-alkanes. The fractionation became larger as the columns packed with mineral samples aged. When not aged, only small fractionation was observed. These results show that the dehydrated state of the interlayer spaces of clay minerals or the pore spaces of zeolites play an important role in fractionation. Furthermore, these results suggest that the large fractionation by clay minerals or zeolites does not occur under normal subground condition where these minerals are hydrated.

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A quartz porphyry dyke in the Kamioka Pb-Zn-Mo mining district shows large variations of Na, K, Ba and Sr concentrations with sodium negatively correlating to other three elements. These compositional changes are well explained by a model of liquid percolation through the rock, for which a mathematical formula was described by Haskin (1984). The liquid percolation brought about addition of K, Ba and Sr to the rock by compensating Na. Estimated composition for the liquid has K₂O/Ba = 47 and Sr/Ba = 0.14. It is also indicated that D_Na is in inverse proportion to the concentrations of K, Ba or Sr in the liquid.

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